Rotary lifting table

ABSTRACT

The rotary lifting table is equipped with a rotary lifting table plate ( 14 ) for supporting planar articles ( 12 ) and two ejection devices ( 20 ) which are located opposite one another and define a stacking shaft ( 16 ) and are intended for ejecting the stacked planar articles ( 12 ). In addition, it has, according to the invention, a sliding plate ( 26 ) having air discharge openings ( 34 ), through which pressurized air escapes during the removal of a stack of planar articles ( 12 ) and thus makes possible low-friction sliding of the stack from the stacking shaft ( 16 ).

FIELD OF THE INVENTION

The present invention relates to a rotary lifting table according to the preamble of claim 1.

BACKGROUND

Rotary lifting tables for processing planar articles, in particular printed products, such as printed sheets, newspapers, magazines, etc., are generally known. They are equipped with a rotatable and/or liftable and lowerable rotary lifting table plate, on which or above which the planar articles come to lie. Rotary lifting tables have as a rule associated ejection means, by means of which the planar articles lying on the rotary lifting table plate can be pushed out in a selected ejection direction.

The rotatability of the rotary lifting table plate is advantageous in particular when forming stacks of folded printed products. Thus, to increase the stability of such stacks, partial stacks rotated relative to one another in each case by 180° relative to a rotation axis oriented at right angles to the rotary lifting table plate are alternately arranged in layers one above the other. In this way, thicker regions on the fold side and thinner regions of the free side edges of printed products of successive partial stacks in each case come to lie alternately one above the other, such that differences in height of the individual partial stacks on account of their different thicknesses in certain regions are compensated for.

Rotary lifting table plates are preferably liftable and lowerable in order to specifically reduce, for example, drop heights for printed products or partial stacks formed therefrom or, for the purpose of compressing stacks, in order to be able to press said stacks against pressing elements arranged above the rotary lifting table plate.

It is not absolutely necessary in every case to form both the rotatability and the liftability and lowerability of the rotary lifting table plate. On the contrary, the claimed rotary lifting table described below can also be used in a completely analogous manner with restricted functionality, that is to say when used as a rotary table or lifting table, or even only as a stacking table.

A rotary lifting table for supporting printed products is described, for example, in EP-A-1852379. In this case, a rotary lifting table plate is arranged on a rotary lifting cylinder, said rotary lifting table plate being equipped on two opposite sides with ejection devices which have ejection means for ejecting the printed products arranged in a stack. A movement, displacing the printed products, of the ejection means over the rotary lifting table plate defines an ejection device in this case. The rotary lifting table plate has a supporting surface arched convexly upward and having a transverse ridge region, the longitudinal extent of which runs at least virtually at right angles to the ejection direction. The planar articles lying one above the other in the stack are adapted to the arched supporting surface on account of their sheet-like formation and their dead weight and give the stack increased stability due to their profiling.

In particular during the ejection of the stacks of planar products, the problem arises that the dimensional stability of the stack and the intactness of the planar products may be impaired during the ejection.

BRIEF SUMMARY OF THE INVENTION

It is therefore the object of the present invention to improve the dimensional stability and intactness of the stacks of planar articles during their removal from a rotary lifting table.

This object is achieved by a rotary lifting table as claimed in claim 1. Especially preferred embodiments are provided with the features stated in the dependent claims.

The rotary lifting table according to the invention is equipped with a rotary lifting table plate for supporting planar articles, in particular printed products. A stacking shaft is bounded at the bottom at least partly by the rotary lifting table plate, said stacking shaft being defined by two opposite ejection devices, and the planar articles being collected in said stacking shaft in order to form a stack. The ejection devices, by means of which the stacked planar articles can be removed in at least one ejection direction, are mounted on a turntable connected to the rotary lifting table plate in a rotationally fixed manner.

According to the invention, the rotary lifting table is equipped with at least one sliding plate which has air discharge openings. During removal of the stack of planar articles, low-friction sliding from the stacking shaft in the ejection direction is made possible by air being forced from the air discharge nozzles, such that an air cushion is formed between the lowermost planar article of the stack and the sliding plate. Due to the low-friction sliding from the stacking shaft, there is less risk of the planar articles being damaged or of the stack being deformed or collapsing. At the same time, a lower expenditure of force is required by the ejection devices when pushing the stack out of the stack space.

In especially preferred embodiments, the rotary lifting table plate engages in the sliding plate during the ejection of the stack. In a further preferred embodiment, the sliding plate is fixed on the turntable.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

An especially preferred embodiment of the rotary lifting table according to the invention is described in detail below with reference to drawings, in which, purely schematically and in detail:

FIG. 1 shows a rotary lifting table according to the invention in a side view with partial sectional illustration, having a rotary lifting table plate in a lowered and a raised position (dot-dash line) and laterally arranged sliding plates;

FIG. 2 shows, in a plan view, the rotary lifting table shown in FIG. 1, in a basic rotary position with the laterally arranged sliding plates and assigned outfeed conveyors; and

FIG. 3 shows, in a plan view, the rotary lifting table shown in FIG. 1 and FIG. 2, in an end rotary position.

DETAILED DESCRIPTION OF THE INVENTION

The rotary lifting table 10 according to the invention shown in FIG. 1, which is intended for planar articles 12, in particular for printed products, such as magazines, newspapers, paper sheets, etc., has a rotary lifting table plate 14 for supporting the planar articles 12, a stacking shaft 16 being bounded at least partly at the bottom by said rotary lifting table plate 14. The rotary lifting table plate 14 is shown in FIG. 1 in a lowered basic lifting position and in a raised position (dot-dash lines). The rotary lifting table plate 14 is mounted centrally on a rotary spindle device 18 which ensures the liftability and lowerability of the rotary lifting table plate 14. The rotary spindle device 18 is part of a lifting means which can preferably be operated electrically, hydraulically or pneumatically.

The stacking shaft 16 is defined by two ejection devices 20 which are located opposite one another and of which only one can be seen in FIG. 1. The ejection devices 20 are described in detail, for example, in EP-A-1445224. They are equipped with ejection means which are fastened to transport means 22 and are in the form of angle profiles 24. The angle profiles 24 define the stacking shaft 16 laterally and permit the spatially defined formation of stacks of planar articles 12.

To eject the planar articles 12 which are then arranged in a stack, the angle profiles 24 are moved in the ejection directions A, A′, likewise defined by the ejection devices 20, and the stacks are pushed to assigned conveyors, in particular outfeed conveyors 28, in a sliding manner via sliding plates 26 designed according to the invention. A section through one of the sliding plates 26 is shown in FIG. 1 in the partial sectional illustration.

The sliding plates 26 are fixedly arranged on a turntable 30 which rotates with the rotary lifting table plate 14. They have a top sliding surface 32 with air discharge openings 34, from which pressurized air can escape, such that, when a stack of planar articles 12 is being pushed out, an air cushion forms between the lowermost planar article 12 of the stack and the sliding surface 32. The stack of planar articles 12 which is “floating” on this air cushion is pushed in one of the ejection directions A, A′ to the respective outfeed conveyor 28 for ejecting by the angle profiles 24 of the ejection devices 20.

In the interior, the sliding plates 26 have a cavity 36, to which the pressurized air is directed via air feed connections 38, said pressurized air then discharging from the cavity 36 through the air discharge openings 34. In this case, the air discharge openings 34 can preferably widen from the cavity 36 in the direction of the top sliding surface 32. The cross sections of the air discharge openings 34 may of course be adapted to the respective application.

The air feed connections 38 are fluidically connected to a reservoir (not depicted) of pressurized air via air feed lines 40, which are shown by dashed lines in FIG. 1. In the embodiment shown here, the two air feed connections 38 of the two sliding plates 26 are connected to one another via a T piece, and a common air feed line 40A which is directed along the rotary spindle device 18 enters a movable trailing cable 42 via an end arranged fixedly relative to the turntable 30 on the side of the rotary lifting table. Inside the movable trailing cable 42, the preferably flexible common air feed line 40A is directed to a pressure-regulating device 44, shown in FIG. 2 and FIG. 3, and is connected via the latter to the reservoir.

The pressure-regulating device 44 forms a control device for establishing the pressure of the air escaping from the air discharge openings 34 of the sliding plates 26. The air pressure is in this case preferably established as a function of the weight of the supported planar articles and/or of the rotary/lifting state of the rotary lifting table plate 14. It may be noted at this point that the air medium may of course also be replaced by another gaseous medium.

The essentially circular-disk-shaped turntable 30 is rotatably mounted on a table frame 50 via a bell-shaped support 46 by means of a ball bearing 48. The rotary spindle device 18, which extends essentially at right angles to the turntable 30, is arranged coaxially in the interior of the bell-shaped support 46. A rotary movement of the turntable 30, which is connected to the rotary lifting table plate 14 in a rotationally fixed manner, is driven by a belt drive (not depicted), the belt or toothed belt of which rests on the outer circumferential surface of a hub element 52 of the bell-shaped support 46.

The belt drive is operated, for example, by means of an electric motor (not depicted).

The table frame 50 is connected in a rotationally fixed manner to a rotary lifting table housing 54, which has a fixed base plate 56 on the top side.

The stacking shaft 16, formed by the ejection devices 20, and the ejection directions A, A′, in which the associated outfeed conveyors 28 follow, can be seen especially well in the plan view in FIG. 2 of the rotary lifting table 10 according to the invention. As can be seen from the figure, in which the rotary lifting table 10 is shown in a basic rotary position, tongue-like extensions 58 of the rotary lifting table plate 14, which are formed thereon on the wide side, are in engagement with associated, U-shaped apertures 60 of the sliding plate 26. The sliding plates 26 arranged fixedly on the turntable 30 rotate, during a rotation of the turntable 30, about a rotation axis D defined by the longitudinal axis of the rotary spindle device and in the process sweep over the base plate 56 with their radially outer end regions.

During the ejection of a stack of planar articles 12 from the stacking shaft 16, the stack of planar articles 12, in the lowered state of the rotary lifting table plate 14, is pushed by the angle profiles 24 of the two ejection devices 20, which are each driven synchronously, over the rotary lifting table plate 14 in a low-friction, sliding manner via the sliding surfaces 32 of the sliding plates 26 in one of the ejection directions A, A′ onto the directly opposite outfeed conveyor 28.

As can also be seen from FIG. 2, the angle profiles 24, in the free end regions of their legs projecting from the transport means 22, are provided with profile extensions 62 of U-shaped cross section. These profile extensions 62 are preferably formed from an elastic plastic material and reduce the risk of damage to the planar articles 12 when the stack of planar articles 12 is being pushed out.

The opposite ejection devices 20 are each provided, centrally with respect to their longitudinal axis, with format adaptation elements 64 on the outer side opposite the stacking shaft 16. These format adaptation elements 64 permit a displacement of the ejection devices 20 in the longitudinal direction of elongated holes 66 formed in the turntable 30. Further format adaptation can be carried out via a displacement of the angle profiles 24 along the transport means 22 of the ejection device 20.

As can likewise be seen from FIG. 2, the air discharge openings 34 of the sliding plates 26 are arranged in a repetitive pattern, preferably in a regularly distributed manner at least in sections. In this way, an air cushion is formed as evenly as possible under the stack of the planar articles 12. In the process, too rapid an escape of air from the air cushion is reduced by outer end regions of the planar articles 12, lying flat one on top of the other, being arched downward in the direction of the turntable 30 or the base plate 56.

In the basic rotary position, shown in FIG. 2, of the rotary lifting table 10, as is assumed, for instance, when ejecting a stack of planar articles 12, the movable trailing cable 42, in which the common air feed line 40A is guided, describes an essentially U-shaped bend. During a rotation about the rotation axis D in a direction of rotation DR, as indicated in FIG. 2 by an arrow, through 180°, the end rotary position shown in FIG. 3 is assumed.

In this end rotary position, the movable trailing cable 42 together with the common air feed line 40A is rearranged in a worm shape. During the changeover from the basic rotary position into the end rotary position, the sliding plates 26 are each moved toward the outfeed conveyor 28 arranged opposite in the basic rotary position. During the rotation of the stack of planar articles 12, the ejection directions A, A′ are therefore oriented toward the respective other outfeed conveyors 28.

FIG. 3 indicates how the stack of planar articles 12 is moved from the rotary lifting table plate 14 via the sliding plate 26 to the assigned outfeed conveyor 28 by synchronous movement of the angle profiles 24 together with their profile extensions 62 in the ejection direction A′.

The specific form of the sliding plates 26 and of their sliding surfaces 32 may of course be adapted to the specific requirements. It is thus possible, as in the exemplary embodiment described, for the sliding plates 26 to extend into the stacking shaft 16 or to first be arranged outside the stacking shaft.

In addition, it is possible to also provide the rotary lifting table plate 14 with air discharge openings 34 like the sliding plates 26, pressurized air escaping from said air discharge openings 34 to produce an air cushion under the stack of planar articles 12. Contrary to a rotationally fixed arrangement of the sliding plates 26 on the turntable 30, as in the exemplary embodiment described above, it is also conceivable to fasten the sliding plates 26 to the base plate 56 of the rotary lifting table housing 54 in a fixed position. In addition to the flat sliding surfaces 32, running essentially horizontally in the exemplary embodiment described, of the sliding plates 26, inclined or profiled sliding surfaces 32 are of course also conceivable.

In all these cases, however, as in the exemplary embodiment described, low-friction sliding of the stack from the stacking shaft 16 in the ejection directions A, A′ to associated outfeed conveyors 28 is made possible by means of the air cushion produced under the stack of planar articles 12. 

1. A rotary lifting table having a rotary lifting table plate (14) for supporting planar articles (12), in particular printed products, and two ejection devices (20) which are located opposite one another and define a stacking shaft (16) and by means of which stacked planar articles (12) can be removed in at least one ejection direction (A, A′), the stacking shaft (16) being bounded at the bottom at least partly by the rotary lifting table plate (14), and the ejection devices (20) being arranged on a turntable (30) connected to the rotary lifting table plate (14) in a rotationally fixed manner, comprising a sliding plate (26) which has air discharge openings (34) and makes possible low-friction sliding from the stacking shaft (16) in the ejection direction (A, A′) during the removal of the stack of planar articles (12).
 2. The rotary lifting table as claimed in claim 1, wherein the sliding plate (26) extends into the stacking shaft (16).
 3. The rotary lifting table as claimed in claim 1, wherein the sliding plate (26) is arranged to rotate with the rotary lifting table plate (14).
 4. The rotary lifting table as claimed in claim 3, wherein the sliding plate (26) is fastened to the turntable (30).
 5. The rotary lifting table as claimed in claim 1, wherein the rotary lifting table plate (14) and the sliding plate (26) are in engagement with one another during the removal of the stack of planar articles (12).
 6. The rotary lifting table as claimed in claim 1, wherein pressurized air can escape from the air discharge openings (34) in such a way that an air cushion forms between the lowermost planar article of the stack of planar articles (12) and a sliding surface (32), facing this lowermost planar article, of the sliding plate (26).
 7. The rotary lifting table as claimed in claim 6, wherein the air discharge openings (34) widen toward the sliding surface (32).
 8. The rotary lifting table as claimed in claim 1, wherein the air discharge openings (34) are arranged in a repetitive pattern, preferably in a regularly distributed manner at least in sections.
 9. The rotary lifting table as claimed in claim 1, wherein a flexible air feed line (40, 40A) is guided in a movable trailing cable (42) for feeding pressurized air to the sliding plate (26), said trailing cable (42) being fixedly arranged relative to the turntable (30) on the side of the rotary lifting table.
 10. The rotary lifting table as claimed in claim 1, wherein two ejection directions (A, A′) having a diametrically opposite sense of direction are defined by the stacking shaft (16), and one sliding plate (26) each is arranged in a respective ejection direction (A, A′).
 11. The rotary lifting table as claimed in claim 1, wherein the sliding plate (26) extends between the stacking shaft (16) and an associated conveyor, in particular an outfeed conveyor (28).
 12. The rotary lifting table as claimed in claim 1, wherein the rotary lifting table plate (14) is also provided with air discharge openings (34), from which pressurized air can escape.
 13. The rotary lifting table as claimed in claim 1, wherein the pressure of the air escaping from the sliding plate (26) is preferably established as a function of the weight of the supported planar articles (12) and/or of a rotary/lifting state of the rotary lifting table plate (14) via a pressure-regulating device (44). 